Dimer conformation of soluble PECAM-1, an endothelial marker
Dimer conformation of soluble PECAM-1, an endothelial marker
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可溶性 PECAM-1（内皮标记物）的二聚体构象
DOI：
10.1016/j.biocel.2016.06.001
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发表时间：
2016-08-01
影响因子：
4
通讯作者：
Huang, Mingdong
中科院分区：
文献类型：
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作者：
Jiang, Longguang;Lin, Lin;Huang, Mingdong
血小板内皮细胞粘附分子-1（PECAM-1）是一种广泛分布于内皮细胞和造血细胞表面的细胞表面受体，维持血管的完整性。PECAM-1被广泛认为是内皮细胞标志物。通过PECAM-1的细胞外结构域（可溶性PECAM-1，或sPECAM-1）的嗜同性相互作用对其功能是重要的。然而，这种二聚化的结构细节尚未完全理解。本文报道了利用果蝇表达系统大量表达重组sPECAM-1，并对其进行了小角X射线衍射（SAXS）研究。发现重组sPECAM-1形成一个二聚体群体，但不是寡聚体，并且能够在表面等离子体共振成像（SPRi）结合实验中与固定在芯片上的肝素结合。小角X射线散射（SAXS）结果表明，sPECAM-1在溶液中形成了对称的Ω型同源二聚体，每一个原聚体均呈伸展构象。二聚体通过sPECAM-1的第一个N-末端结构域（D1）的分子间相互作用介导。这一模型为它的亲均作用机理提供了新的结构信息。(C)2016爱思唯尔有限公司版权所有。
Platelet endothelial cell adhesion molecule 1 (PECAM-1) is a cell surface receptor widely distributed on endothelium and hematopoietic-derived cells, and maintain the integrity of the blood vessels. PECAM-1 is widely recognized as an endothelial cell marker. The homophilic interaction through its extracellular domain of PECAM-1 (soluble PECAM-1, or sPECAM-1) is important to its functions. However, structural details for such dimerization are not fully understood. Here we report the production of recombinant sPECAM-1 in large quantity by Drosophila expression system and the small-angle X-ray diffraction (SAXS) study. The recombinant sPECAM-1 was found to form one population of dimer, but not oligomer, and was able to bind to heparin immobilized on a chip in surface plasmon resonance imaging (SPRi) binding experiments. The results of SAXS demonstrated that sPECAM-1 formed a symmetric homodimer of Omega-shape in solution, and each protomer adopted an extended conformation. The dimer is mediated through the intermolecular interactions through the first N-terminal domain (D1) of sPECAM-1. This model provides new structural information for its homophilic interaction mechanism. (C) 2016 Elsevier Ltd. All rights reserved.